The Importance of Checking Blood Sugar Levels

Besides helping to keep blood sugar levels (also known as blood glucose levels) under control, checking them according to the diabetes management plan will help you and your child:

• feel more aware and in control of what is happening with your child's diabetes
• prevent short-term diabetes symptoms and future health problems
• troubleshoot problems and make adjustments to the diabetes management plan more promptly and effectively
• manage sick days
• gain a better understanding of the impact of food, exercise, and medications on the blood sugar levels

When and How Often

How often you should test your child's blood sugar levels each day — and when — will depend on a number of things and can even change from day to day. In general, most kids with diabetes test their blood sugar levels before breakfast, lunch, and dinner, and at bedtime.

They may need to check more often when they're sick or if there are changes in their diabetes treatment or daily habits. They may also need to check more often if they use an insulin pump or another management plan that aims for very close control of blood sugar levels. The diabetes health care team can advise you on how often and when to check.

Sometimes parents need to check their child's blood sugar levels in the middle of the night. For example, kids having problems with hypoglycemia episodes may need middle-of-the-night tests. And those who've just been diagnosed with diabetes may need more frequent tests while they and their families are learning how insulin or other diabetes medicines affect blood sugar levels.

How to Check Blood Sugar Levels

Blood glucose testing is easier, less painful, and more accurate than ever. Blood sugar levels can be tested with a blood glucose meter, a computerized device that measures and displays the amount of glucose in a blood sample.

To get a blood sample, a small needle called a lancet is used to prick the skin (usually on a finger or the forearm) to draw a drop of blood. The drop of blood is placed on a testing strip that goes into the glucose meter, and the blood glucose reading appears on a screen within a few seconds.

How do you know which glucose meter to use? Most people with diabetes choose the type of equipment covered by their insurance plans. However, many types of glucose meters are available with different features.

When choosing a glucose meter, consider:

• Cost: Although most insurance plans cover the cost of glucose meters and test strips, there may be a limit to the number of test strips they cover (and test strips are the most expensive part of monitoring blood sugar levels). Make sure you know what your insurance will cover before investing in a glucose meter.
• User-friendliness: Choose a glucose meter that is easy to use and maintain. For example, a glucose meter that doesn't require large blood samples might be better for young kids, while an easy-to-calibrate meter might be better for teens taking on more of their own diabetes care. Glucose meters that take less time to give results may also be preferred.
• Special features: Glucose meters are available in both large, easier-to-handle sizes as well as small, more portable sizes. Other features may include memory storage and the ability to record additional information like date, time, food intake, and exercise. The ability to download glucose readings into a computer program is an attractive feature for many families.

New Technologies

Other new technologies make it easier to keep track of blood sugar levels. Adjustable lancets can make finger pricks less painful by changing the depth to which the needle enters the skin. Certain glucose meters can use blood drawn from a forearm or other body parts that may be less sensitive than a fingertip. Your diabetes health care team will help you choose the best type of equipment for your child.

In some cases, a doctor might want to get an even more detailed look at the blood sugar level fluctuations throughout the day and night. A wearable device can measure blood sugar levels every 5 minutes over a 3-day period, then a computer printout of the person's blood sugar profile can be downloaded at the end of the test for the doctor to evaluate. A sensor must be inserted under the skin and the results interpreted by a medical professional.

This testing is not practical for routine blood sugar monitoring because the sensor would have to be replaced every 3 days and the results cannot be viewed until the 3-day testing period is over.

Other Tests

Hemoglobin

The glycosylated hemoglobin (hemoglobin A1c or HbA1c) test will give you an overall picture of what your child's blood glucose control has been over the 2 to 3 months before the test and is usually done during regular clinic visits with the diabetes health care team.

Hemoglobin is the substance inside red blood cells that carries oxygen to the cells of the body. The higher the glucose level is in the blood, the more it sticks to the hemoglobin. And once hemoglobin picks up glucose, the glucose stays on it for the life of the red blood cell, which is about 2 to 3 months.

The most commonly measured type of hemoglobin in the blood that has glucose attached to it is called HbA1c. In general, the lower (and closer to the levels seen in people without diabetes) your child's HbA1c, the better controlled the blood sugars have been over the preceding 2 to 3 months. Having lower HbA1c levels over years is associated with a lower risk of future health problems related to diabetes.

Ketones

Another important test checks for ketones, chemicals that show up in the urine and blood after the body breaks down fat for energy. The body will break down fat when it can't use glucose; for example, when there isn't enough insulin to help the glucose get into the cells or not enough food has been eaten to provide glucose for energy (such as when a child is ill).

Having lots of ketones in the body can put a child at risk for a major diabetes emergency called diabetic ketoacidosis, which can make kids very sick. So it's important to test for ketones when necessary before they build up in the body. It's an easy test to do at home.

The diabetes health care team will let you know how and when to test for ketones (usually when your child is having consistently high blood sugar test results or is ill with vomiting or other symptoms of diabetic ketoacidosis). They'll also teach you how to interpret the results as part of your child's overall treatment plan.

Record Keeping

While glucose meters can help keep track of your child's blood sugar tests, writing down the results will make it easier for you and the diabetes management team to see patterns and trends. This will help you and your child better understand the link between food, exercise, and blood sugar levels, and also help you and the health care team make any needed adjustments to the diabetes management plan.

Reviewed by: Steven Dowshen, MD
Date reviewed: August 2010